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MaxEnt is useful here too. We last saw MaxEnt in the NLTK default tagger What is it doing?. Logistic regression. Very common machine learning technique Assign a positive/negative value to every feature Add up the values for features that are present The logit function tells
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MaxEnt is useful here too • We last saw MaxEnt in the NLTK default tagger • What is it doing?
Logistic regression • Very common machine learning technique • Assign a positive/negative value to every feature • Add up the values for features that are present • The logit function tells you the probability • Learn the best values
Example: movie reviews • funny = +1 • disappointed = -2 • seagal = -3
High-level overview of MaxEnt • Now you have something more complicated than a yes/no question • You’re learning probability distributions instead of probabilities • The best probability distributions are the ones that are maximally uninformative about things you don’t know • Do things you’ve never observed happen 0% of the time? No, that’s assuming information you don’t have.